Blogs, magazines, and online journals give you a deeper sense of how your topic is being discussed right now. Look up the leading blogs in your niche and note what subjects they cover most often.

Are there themes that appear everywhere?

Are there subtopics that rarely get attention?

Those less-covered areas could be perfect for your book.

Also observe tone and structure. Are articles personal, research-based, or story-driven? This helps you understand what readers respond to and how you might differentiate yourself.

Read comments sections when available. Readers often share what resonated with them or what they still need help with.

If you notice that several blogs focus heavily on theory but few provide step-by-step guidance, you could write a practical book that fills that gap. Or if most articles focus on beginners, you might create a book aimed at intermediate or advanced readers.